The invention relates to a coupling to permit filling and sealing of a pressurizable casting mold with a flowable polymer, the polymer being delivered through a nozzle which is inserted into a port on the mold. In such a coupling, the nozzle relates to pinch valves and the port relates to spherical closure valves. The coupling is useful with the mold fill system generally disclosed in U.K. No. 2,052,359 where an undefined closure element provides pressure-tight access to a casting runner. Such a system generally requires significant manual effort to use. Timely cleaning is required during the filling process.
It is sometimes desirable to fill such a mold from the bottom to facilitate removal of air from the mold during filling. With such a coupling as in U.K. No. 2,052,359, the mold must be reoriented so the port is above the fluid level before the nozzle is removed and the port capped, otherwise, the flowable fluid would run out of the mold.
Pinch valves of a type that may be useful in a coupling nozzle are known. U.S. Pat. No. 4,268,005 features a pressure-closable elastomeric sleeve inside an outer sleeve. The construction of such a valve is especially adapted for use with large size ducts and conduits of 8 to 12 feet in diameter. Such a valve, even if it could be scaled down to be suitably incorporated into an inch-scale diameter nozzle, requires an internal ring to retain and seal the elastomeric sleeve to the housing; such a ring restricts flow of fluid through the sleeve and creates stagnant flow areas for the fluid.
U.S. Pat. No. 3,982,723 discloses a pinch valve of simple construction where a thin wall flexible tube is folded back over the end of a tubular housing. End tubes are passed over the folded end and compressed by external clamps to retain and seal the flexible tube to the housing. Conduits are inserted at the ends of the valve and are held by the compressed end tubes. The external clamps on the tube ends would prevent insertion of the complete end of the valve into a close fitting hole.
Spherical closure elements useful in a coupling are known. U.S. Pat. No. 1,043,451 provides a door or closure on a boiler which can be opened and closed readily and will permit the free introduction of a nozzle without permitting the escape of fluids that pass into the boiler while the nozzle is in place in the closure. This is achieved by providing, at an opening into the boiler, a spherical bearing or support and mounting therein a spherical closure which has through it an aperture to permit the passage of the nozzle. The spherical closure can be turned, when the nozzle is removed, so as to close the aperture completely. The nozzle must be removed completely before the closure can be turned to close the aperture. During the time the nozzle is removed and before closing the aperture, any pressurized fluid in the boiler, such as would be the case where the aperture is located at the bottom of the boiler, can escape through the aperture, which is undesirable. The spherical closure of U.S. Pat. No. 1,043,451 also must have a projecting pin by which it can be turned to expose or conceal the aperture. This pin and the nozzle must be separately engaged, such as by an operator, to effect the closure; the nozzle to be removed and the pin to turn the spherical element. This complicates automation of the nozzle and closure handling.